This invention relates generally to measuring devices, and in particular, to a tool for identifying measured cutting lines on workpieces.
There are a number of existing devices that have been separately used by carpenters to assist in marking and cutting various dimensions, such as pitch angles of rafters. However, these devices do not provide for ease of use. For instance, when using a triangular rafter square, the base typically must be aligned with a rafter edge before the square is pivoted about the rafter square pivot to allow the user to align the rafter edge with a measurement indicia on the square. The square typically must then be held in place while the user marks the cutting line along the hypotenuse of the square. Then the square is removed and a cut is made along the marked line. This process may need to be repeated for numerous rafters and is inefficient.
In addition to being inefficient, such squares typically must sacrifice ease of use for the ability to mark or cut long distances, or vice versa. For instance, a typical seven inch rafter square has a hypotenuse of less than ten inches. For cuts longer than ten inches, the user must mark the cutting line and then remove the square from its initial position and place a straight-edge along the cutting line to provide for further markings beyond ten inches. While it is possible to use rafter squares having much longer hypotenuses, such squares are awkward in use due to the required leg lengths and are difficult to carry at the job site.
There remains a need for a simple, durable, inexpensive, multi-purpose device which is capable of accurately preparing cutting lines for roof rafters, allows for ease of use and provides for long cuts without being difficult to store or carry. Such a device should be compact, portable, easy and rapid to use and not require the use of any additional or supplemental instruments. An improved tool and method of use thereof which addresses these needs would be an important advance in the art.
The adjustable tool of the current invention provides a means for repeatedly identifying desired cutting lines without requiring re-measuring steps. The adjustable tool of the current invention also provides for the identification of several different desired cuts during construction of rafters by a single device that fits easily into the carpenter""s tool pouch. Furthermore, the tool allows for the elimination of marking steps since it provides for cutting along its straight-edge while engaging the workpiece. The tool also satisfies the other noted needs in the field.
It is an object of the invention to provide an improved tool for cutting workpieces.
Another object of the invention is to provide an adjustable tool which has a movable pin which can be adjusted and secured to provide for identical repeated cuts on successive workpieces
Another object of the invention is to provide an adjustable tool which allows for accurate cutting of workpieces without requiring the marking of the workpieces before cutting.
Another object of the invention is to provide an adjustable tool which is easily stored and transported in a carpenter""s tool pouch.
Another object of the invention is to provide a tool which has a post and pin which separately engage a single workpiece border to provide a cutting line across the surface of the workpiece.
Another object of the invention is to provide a tool which has a post and pin which is movable independent of the post to provide the ability to engage a single workpiece border at to provide a cutting lines at various angles across the surface of the workpiece.
Another object of the invention is to provide a tool which identifies a desired cutting line on a workpiece and includes a handle to grip during cutting.
Another object of the invention is to provide a xe2x80x9cbxe2x80x9d-shaped tool which allows identification of cutting lines on a workpiece.
Another object of the invention is to provide a tool which engages a workpiece during cutting and provides fixed cutting lines at any angle between 0xc2x0 and 90xc2x0.
Another object of the invention is to provide a method of use of the improved adjustable tool which allows users to efficiently cut along desired cut lines of successive workpieces without requiring any re-measurement.
Still another object of the invention is to provide a method of use which provides for cutting of a workpiece without removing the line-identifying tool from the workpiece surface.
Yet another object of the invention is to provide a method of producing common-rafter, hip-rafter and seat cuts using a tool having a fixed post and an adjustable pin which engage the border of the workpiece being cut.
How these and other objects are accomplished will become apparent from the following descriptions and the drawings.
This invention is an adjustable tool for use in cutting workpieces, such as rafters, which have faces extending between first and second opposite borders. The invention represents a significant advance over the state of the art by providing novel elements which can be utilized in a novel method to efficiently cut workpieces along desired cutting lines.
The adjustable cutting tool includes an elongate guide member, a post fixed to the guide member, an arm extending from the guide member and defining a slot, and a movable pin positioned in the slot and adapted to be secured at a desired location corresponding to a desired measurement indicium. The arm defines first and second external edges while the slot defines first and second internal edges. Each of these four edges may have measurement indicia marked thereon, including common-rafter, hip-rafter, seat cut and/or angle degree measurement indicia. The arm and slot are both preferably curvilinear.
The guide member has a proximal and distal end, a top and bottom surface and a primary and secondary side. The primary side includes a straight-edge which preferably has indicium indicating English or metric length units. The arm and a handle preferably extend from the secondary side and connect to form a void with the handle being adapted to be gripped by a user during cutting of a workpiece. It is preferred that the guide member, arm and handle be integrally formed.
The post is preferably fixed to the proximal end and is perpendicular to the guide member. In certain preferred embodiments, the post is formed integrally with the guide member. The post preferably extends beyond the bottom and/or top surface. The pin is preferably a bolt or of similar construction and also extends beyond the bottom and/or top surface. In certain embodiments, the pin is adapted to be secured at a location in the slot corresponding to a desired measurement indicium by using a tightening mechanism, e.g., by tightening a nut on the pin. When the pin is secured at a desired location, the post and pin are adapted to simultaneously contact the first border of the workpiece so that the straight-edge identifies a desired cutting line corresponding to the desired measurement indicium.
In certain embodiments, the tool includes a notched groove for providing the ability to insert a marking instrument therein and by sliding the tool along the workpiece while the post and pin engage the first border to scribe the workpiece.
In certain embodiments, the tool includes at least one level mounted within the tool normal to the straight-edge and parallel to the bottom surface. In other embodiments the tool includes at least one level mounted within the tool parallel to the straight-edge and to the bottom surface.
The invention can also be described as a tool which includes: 1) an elongate guide member having a midpoint equidistant from a proximal and distal end, a bottom surface and a primary side, the primary side including a straight-edge; 2) a post fixed at the proximal end; 3) an arm connected to the guide member between the proximal end and the midpoint, the arm having measurement indicia marked thereon and first and second external edges with a slot therebetween; 4) a movable pin positionable in the slot, the pin adapted to be secured at a desired location corresponding to a desired measurement indicium; and 5) a handle connected to the guide member at the proximal end, the handle connected to the arm to form a void. In such a tool, the post and the pin are adapted to simultaneously engage the first border of the rafter while the bottom surface rests on the face of the rafter so that the straight-edge identifies a desired cutting line corresponding to the desired measurement indicium. In addition, the handle of such a tool is adapted to be gripped while the post and pin engage the first border to enable a user to ensure engagement between the post and pin and the first border during cutting.
In such a tool the slot preferably defines first and second internal edges which, along with the first and second external edges, have measurement indicia marked thereon. Most preferably, common-rafter indicia is marked on the first external edge, hip-rafter indicia is marked on the first internal edge, seat cut indicia is marked on the second internal edge and angle indicia is marked on the second external edge.
It is further preferred that the guide member, post, arm and handle be integrally formed. In addition, it is preferred that the movable pin include a tightening mechanism which can be loosened to allow the location of the pin to be adjusted and tightened to secure the pin at the desired location.
In certain preferred embodiments the tool is xe2x80x9cbxe2x80x9d-shaped such that it includes 1) an elongate distal portion which is sufficiently long as to identify any desired cutting line without requiring use of another tool to extend the cutting line, and 2) an annular portion connected at the proximal end and including a portion having measurement indicia and a handle portion.
The invention also includes a method of cutting a rafter along a desired cutting line which comprises providing the adjustable tool, securing the moveable pin at a desired location corresponding to a desired measurement indicium; placing the bottom surface of the guide member on the face of the rafter so that the post and pin engage the first border of the rafter; and cutting the rafter along the straight-edge.
In the preferred method the tool comprises an elongate guide member having a proximal and distal end, a bottom surface and a primary side, the primary side including a straight-edge; a post fixed at the proximal end; an arm extending from the guide member, the arm having measurement indicia marked thereon and first and second external edges with a slot therebetween; and a movable pin positionable in the slot. In certain embodiments, the tool may further include a handle adapted to be gripped by a user while the user cuts the rafter. In such embodiments the method also includes the step of gripping the handle and holding the tool so that the post and pin remain engaged with the first border during the cutting step.
It is preferable that the cutting step be performed while the post and pin engage the first border so that the desired cutting line need not be marked on the rafter. In other words, the user need not position the tool, mark the cutting line, remove the tool and then cut the rafter. Instead, the user need only position the tool and cut the rafter while holding the tool.
The inventive method also provides that the placing and cutting steps be repeated for a second rafter which results in first and second rafters having identical cuts without requiring measurement of the angle between the cut and the first border before cutting the either rafter. That is, once the desired measurement indicia is identified and the movable pin is secured at a location corresponding to the desired measurement indicia, repeated cuts can be performed on successive rafters without requiring any angle measurement of the rafters or marking of the rafters. In fact, by adjusting and securing the position of the movable pin in the inventive method angle measurements on the rafters are never required.